KP/Airform 1/72 Spitfire VII (conversion)

HISTORY

During WWII many variants of the Spitfire were developed with generally improvement in performance of the plane. The Spitfire was a streamlined slim aircrraft with elliptical wing, which fought on all fronts in WWII. There were numerous conversions of the basic construction, thanks to the great adoptability of the airframe. By mid 1942 it was time to improve further the Spitfire performance as the rival German FW 190 was by then proving superior to the Spitfire. This was done by installing the new Merlin 61 engine with four-blade airscrews propeller in a basically Mk V airframe that proved more than a match for Germany’s top fighter aircraft. The then developed Mk IX was used for low altitude operations and ground attack missions.

 There were further development of the Spitfire and new versions emerged. A particular type was the Spitfire Mk VII (HF VII) also referred to as Supermarine Type 351 in the development stage. This was a limited production and catered for high flying. 140 aircraft of the type were produced.  As it was planned for the Merlin 61 series 61 engines it necessitated a re-strengthened fuselage and extended engine bearers and cowling. The latter being louvered for the Marshall blowers. It differed from the Mk VI in having ‘C’wing with reduced span ailerons, a retractable tail wheel besides other details. As such it constituted the first major re-design of the Spitfire series to go into production. There were the F and HF versions but since the F version had Merlin 61 or 64 engines of which 724 and 182 respectively were built, the HF used the Merlin 71 of which only 16 were produced as such.

 From the recognition point of view, the loss of the Spitfire’s asymmetrical feature was of considerable importance. This was due to the usual starboard under wing radiator being paired by a similar structure under the port wing, by a redesign of the cooling system. The structure was not identical, although both contained coolant radiators; the starboard structure accommodated the supercharger intercooler and the port structure housed an oil cooler. Another change to the outline was the Spitfire Mk XII type of rudder, introduced in late production models.

 After the Mk VII had outlived its usefulness as a high altitude fighter it was used for meteorological work, being finally withdrawn from service in 1947. The HF VII was powered by a Rolls Royce Merlin 71, driving a 4-blade ‘Rotol’ airscrew. This was either Type R3/4FS/3 with Dural blades or R3/4FS/4 with Hyduligrum blades. The HF VII had a service ceiling of 43,000ft. Normal range was 660 miles. The tankage consisted of two fuel tanks one on top of the other, situated forward of the cockpit with capacity of 47 gallons (upper) and 49 gallons (lower), also two wing tanks of 14 gallons each making a total of 124 gallons fixed tank capacity. Auxiliary drop tanks of 30, 90, 170 gallons could be fitted under the fuselage. An oil tank of 7.5 gallons capacity could be fitted at the rear of the fuselage on early aircraft but on main production aircraft a tank of 8.5 gallons capacity was fitted below the engine mounting.

The conversion kit to make a Spitfire Mk VII issued by an Italian firm ‘Airform’was acquired long ago and at the time there was no kit for this version issued to a scale of 1/72. The conversion kit was used in combination with a Spitfire Mk HF (IX) under the KP trademark. ‘Airform’ suggested that the conversion kit had enough component parts to convert a Hasegawa Spitfire Mk1 into a MkII; the Airfix kit into a Mk V tropical and the Matchbox kit for a Mk VII. This conversion pack in dark brown injection molded plastic was released in mid 80s when most versions of the Spitfire were not yet on the market. The Spitfire conversion kit could also be adopted with other Spitfire models. This is how I found out that I could use the KP kit to convert it into a Mk VII. The ‘Airform’ kit consisted of a single fret containing 32 pieces. There are parts that for this conversion which are not needed such as the tropical intake, 3-blade prop spinner, 2 out of 4 detailed canons etc but other items as the cockpit canopy, and 7 items including rudder pedals, seat, floor and front and back firewalls and control column were better than the KP offering and therefore were used instead. The principal conversion item is the upper wingspan that replaced the kit parts. This had the extension of the wing tips, two pitot tubes instead of one, more detailed cannons and additional parts to represent the aft wheel well doors since the tail wheel was retractable, and also an elongated air intake item to fit to starboard nose.

Like any project I had to make a decision so that things go on smoothly and decided to go ahead with what I had. I just wanted to have the Spitfire VII in my collection and was not keen on detailing the kit more than superficially. The first stage involved trimming the lower wing parts No 14 of the KP kit, and merge it to the ‘Airform’ upper wing parts and there we have the new extended wing span with the taper pointed wing tips which along with more powerful engine gave the Spitfire type high altitude service performance. In doing so I noticed that these had slightly smaller wing ailerons. Any surface detail that disappeared during the smoothening of the surface combination was then re-scribed while the joining areas were treated with a small amount of filler. The exhaust stacks on both sides were then drilled open with a 1mm diameter drill. The assembled new cockpit was then fitted inside the fuselage half, paint detail applied and the fuselage halves closed. The rest will follow as per KP kit instructions.

 I did not go into the gory detail of drilling open the rear tail wheel well for the retractable tail wheel as the area at this scale was so small but instead filed flat a recess covering the well length and drilled a hole to insert the tail wheel followed by fitting in place the tail wheel doors that came with the conversion kit. The leading edge guns were also replaced with new ones provided and an air intake scoop added to the mid lower fuselage while a 90-gallon belly tank was fixed in place. A metal aerial was shaped with a flat file to a pointed taper top end and inserted in a predrilled hole aft of the cockpit. I also used surgical tubes for the outer gun barrels that were inserted in holes drilled at their location on the leading edge. Two under wing pitot tubes (instead of one, as stated earlier) were fitted as carried by the Mk VII. A 4-bladed spinner was assembled and painted ready to be added to the kit as a last item as were also the main wheels.

The high altitude Spitfire was finished in light gray upper surface camouflage using Compucolor brand paint bought 25 years ago. This was followed by carefully masking using Tamiya masking tape and wide areas taped with blank paper. Using blank paper to mask already painted areas may be a measure to economize on Tamiya tape but more to avoid any possible chance that the tape might pull the already airbrushed smooth light gray considering I was using tins of paint bought long ago. All the under wings and undersurfaces were then airbrushed in PRU blue again using Compucolor brand of paint being amazed at how it retained its consistency quality properties in spite of age. The interiors of wheel well, cockpit and wheel legs were in interior green and zinc chromate finish using Humbrol brand.

The kit was given an overall coat of Klear prior to adding decals. Stenciling decals that appear above and below the wings came from an extensive stash of Extradecal sheets and Modeldecal sheets that I’ve collected over the years. Appropriate roundels also came from the spare decal box, mainly Modeldecal brand. The kit was in the end given an overall semi gloss Micro finish giving the kit the fine sheen it seems to wear in photos of the full-scale aircraft.

This was an uncomplicated and fast conversion considering that it basically involved principally a replacement wing. Very little effort was at all needed for this somewhat long ago release conversion set yet it provided a not so common type of Spitfire which differed so much from other types like the MkVb.         

Spitfire-the story of a Famous fighter. A Harleyford Publication by Bruce Robertson.

 Carmel J. Attard

September 2009